Unwanted output in "debug ip packet"

[g.mundell]

Hi everyone,

I have been using "debug ip packet" on a Cisco 2921 running IOS 15.1(4)M1. The problem I have is that, although I am using an ACL to limit the output, I am seeing some output that is distracting from what I am trying to see. Specifically, I am seeing the following:

Mar 19 20:22:36.135:  IP: s=192.168.20.253, d=224.0.0.2, pak 30DB6D4C consumed in input feature , packet consumed, MCI Check(80), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

Mar 19 20:22:38.951:  IP: s=192.168.20.253, d=224.0.0.2, pak 2A74FFE8 consumed in input feature , packet consumed, MCI Check(80), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

These would appear to be HSRP messages. But I don't understand why they are appearing when I configure "debug ip packet 101". The ACL is pretty simple:

access-list 101 permit icmp host 96.87.145.1 host 192.168.20.1

access-list 101 permit icmp host 192.168.20.1 host 96.87.145.1

So I thought the implicit "deny ip any any" would block these messages. I even tried to block them specifically using an extra line:

access-list 101 deny   udp host 192.168.20.253 host 224.0.0.2 eq 1985

But still they show up! Any ideas?

Thanks, Graham

[susdas · Accepted solution]

Hi Graham

The router seems to be hitting the bug CSCtx12810:

     http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCtx12810

I would let you know the IOS versions which would contain a fix for this bug.

Regards

Sush

[susdas]

The IOS versions from 15.2(1)T2 onwards should contain the fix for this bug.

Sush

[g.mundell]

Awesome! Thanks Sush!

I shall now have a think about whether it's worthwhile upgrading the IOS just to get around this bug